Thursday, February 26, 2015

Eastern Bluebirds are one of the most popular and enjoyable birds to have around your home. They don't mind being near people and their activities, and, like many other birds, they recognize you when you're providing food. Bluebirds that are familiar with you will even fly toward you when you are filling their mealworm feeder.

Our nesting Eastern Bluebirds in Tennessee are non-migratory and remain here year-around. They are joined by birds from neighboring states and young bluebirds from neighboring territories to form small wintering flocks that aid winter survival. These flock members help each other find food, spot predators and provide warmth when they roost together in a sheltered cavity, such as a nest box, when the temperature drops below 20 F degrees.

Bluebirds are not your typical feeder birds, however. Their natural winter diet consists of spiders, berries and fruits. If these foods are available they can maintain fat reserves that sustain them during the extreme cold. T. David Pitts, in his book, Studying Eastern Bluebirds, A Biologist's Report and Reflections, also says the following: "As a result of their high rate of metabolism, bluebirds can quickly use the fat they store. If extremely cold temperatures linger for several days, many bluebirds may die since they normally store only enough fat to protect themelves for a day or so, and they may not be able to find enough food to replace the fat that has been used."

A male Eastern Bluebird feeding on the berries of the burning bush.

Pitts also conducted extensive studies in northwest Tennessee that revealed that bluebirds do not digest the seeds that are in the fruits they eat. These seeds pass through their system undigested and provide no nutritional benefit. Herein lies the challenge. A non-seed eating bird that primarily recognizes insects, spiders and berries as food. How do you feed them when winter gets rough?

And even more challenging, how do your feed them when larger, territorial birds are chasing them away from the berry sources?

Female Eastern Bluebird, above and below.

I had this challenge over the past week, when freezing rain and sleet coated everything with ice and temperatures plummeted to single digits with windchills below zero. Suet crumbs froze, mealworms froze and larger birds, such as American Robins and Mockingbirds became aggressive, chasing smaller birds, like bluebirds and Hermit Thrushes away from the berry bushes. In fact, one robin was so territorial he chased bluebirds away from both the holly and the neighboring burning bush.

One male bluebird was familiar with the mealworm feeder guard and could navigate through it and eat suet and mealworms offered there, protected from larger birds. The other bluebirds that came with him did not know how to navigate the guard. With feathers fluffed against the cold and mealworms frozen motionless, there was little hope they would learn about the guard in sub-freezing conditions.

After consulting friends, Billie Cantwell and Liz Cutrone at Knoxville's Wildbirds Unlimited, I adjusted a Dinner Bell feeder to exclude larger birds by lowering the dome cover to a few inches above the tray, filled the tray with smooth "butter bark" suet pellets, small home-made suet crumbs and freeze-dried mealworms and hung it near the bluebird feeder. When the male bluebird came to the feeder, his companions soon discovered the added food source and were also able to eat from it. In their absence, I noticed the Hermit Thrush landing on the dinner bell also to eat suet.

Additional good advice-- spread your suet feeders out so if a larger bird claims one feeder, there is an alternate area for the smaller birds to visit.
In the spring you can also consider planting Sumac near the borders of your yard. In Pitts' studies in northwest Tennessee, two native species, smooth sumac and winged sumac, were the most favored fruit of bluebirds, composing 50-90% of their winter diet even when a variety of other fruits were available.

Pitts advises to plant more than one sumac spaced apart in different areas of the yard to prevent mockingbird dominance. If a group of robins or cedar waxwings flies in and takes over the holly berry supply, a protective mockingbird will likely take over the sumac next. Planting shrubs spaced far apart in different areas will give the bluebirds an alternative choice for feeding.

Sunday, February 22, 2015

Ice presents stressful winter conditions, not only for people, but for wildlife. Though beautiful to witness from warmth and safety, a wintery mix of precipitation that coats food sources presents challenges for bird survival.

In Tennessee we have birds that live here year-around and remain for the winter because of the generally moderate winter conditions and abundance of food. If enough food is available, many bird species can survive temporary plummets in temperature. Extended periods of sub-freezing temperatures, however, such as the single digits that we recently experienced, and a quarter inch coating of ice over everything increases survival challenges considerably.

The American Robin is one of the species that we call resident birds because they remain during the winter. Many northern robins join our local ones to take advantage of the food sources, so we may see large flocks of robins descending on our yards and visiting fruit producing trees and shrubs. Asian holly is one of the berry producing shrubs that attracts many species of birds, though if you are planting holly, the native American Holly is a better choice.

In these images, you see a Robin picking berries from the holly. He not only was feeding on berries, he soon claimed the holly for himself, driving away other robins and also driving away the area bluebirds that came to visit. He ignored sparrows, the Hermit Thrush and did not bother the Mockingbird, the bird we all expect to be territorial with a holly.

The ice and the several days of below 20 F temperatures, presented conditions so stressful, that many birds we normally don't expect to be aggressive were chasing others away from their food source. Above, you see the robin in the act of grabbing another berry. Notice what happens to the berry in the next image.

An ice coated berry is hard to hold on to! People feeding birds during the ice storm and deep freeze temperatures in east Tennessee noticed many territorial birds and an influx of species that weren't commonly seen visiting their winter feeders.

Bird-banding at Seven Islands State Birding Park--2014

Bird-banding at Seven Islands

Enjoying Gray Jays in Churchill!--2014

Smithsonian National Zoo with one of my Whooping Crane banners and son, John--2014

The Incredible Muir Woods near Stinson Beach, CA--2014

Photo courtesy of Wendy Pitts Reeves

Me and Denali--2012

Photo courtesy of Bob King

For the Love of It...

...the sage sees heaven reflected in Nature as in a mirror, and he pursues this Art, not for the sake of gold or silver, but for the love of the knowledge which it reveals.Sendivogius (1750)

Your Uncapped Creativity...

"There is a vitality, a life force, an energy, a quickening that is translated through you into action; and because there is only one of you in all time, this expression is unique. If you block it, it will never exist through any other medium and it will be lost. The world will not have it. You must keep that channel open. It is not for you to determine how good it is, nor how valuable. Nor how it compares with other expressions. It is for you to keep it yours, clearly and directly." ----the great dancer, Martha Graham

Tennessee's Majestic Sandhill Cranes

Autumn Birds Note Cards

Welcome!

Vickie Henderson

Artist, writer, photographer and nature enthusiast, I blog about the experiences that inspire my art. My posts include nature observations and my love for the creative process. For more information about my art visit my "More About Me" page.

Whooping Crane Photo Images

Whooping Cranes

Whooping cranes were on the brink of extinction in the early 1940's with only 15 remaining in the population that migrates from their nesting grounds in Canada to the coast of Texas. Today, after many years of help, this population has reached a record number of 266. In order to safeguard this species, biologists are using an innovative method to imprint captive reared Whooping cranes and teach them to migrate behind ultralight aircraft. In this way, Whooping cranes have been restored to the Eastern flyway and a separate wild migrating population has been established. As more and more people have the privilege of seeing these birds, Whooping cranes have become ambassadors for our wetlands and for all species in need of our assistance. Support our wildlife. Select a favorite project, a favorite place, a favorite species and do your part to help our natural world.